Lecture 11 - Descending Tracts - lecture

Lecture 11 - Descending Tracts - lecture - Higher Centers...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Higher Centers of Motor Control
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Outline 1. 2. Descending pathways a. Dorsolateral pathways b. Ventromedial pathways c. Brainstem reflexes 1. Clinical correlations a. UMN lesions b. Cerebral palsy
Background image of page 2
Higher Centers of Motor Control Involved in voluntary movement Provide motor signals via long descending tracts from the cerebrum These tracts involve the cortex, the brainstem and the spinal cord. UMNs –< interneurons Muscle tone, posture, reflexes and movement are all controlled by a balance of the long descending tracts Like the sensory systems, the motor tracts are a set of parallel pathways, with overlapping and complementary functions.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Overview of Cerebral Cortex Covers the cerebral hemispheres and gives the brain its convoluted appearance; about 2.5 sq. ft Organized topographically (by sensory modality) and somatotopically (homunculus) Six cell layers thick (gray matter) Efferents from the cortex: must be connected with other cortical areas or with subcortical sites
Background image of page 4
Motor Cortex Primary Motor Cortex Controls contralateral voluntary movements Especially the fine movements of the hands and face. Hand, foot, lower face are entirely contralateral. Muscles that tend to be active bilaterally simultaneously are controlled by M1 on both sides. Premotor Cortex Motor planning area Supplementary Motor Cortex Motor planning area Initiation of movement, orientation of eyes & head, planning bimanual and sequential movements All motor cortices above receive info from sensory association areas, BG & cerebellum
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Primary Motor Cortex Somatotopic organization Motor homunculus Has greater representation of hand & lower face, not rigidly fixed Receives info from thalamus
Background image of page 6
Motor Somatosensory Degree of representation is proportional to the precision of movement required by that body part -Face and fingers have LARGE representation
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Descending Tracts Dorsolateral System Control limb flexion & fine movement 1. Lateral corticospinal tract 2. Rubrospinal tract 3. Lateral reticulospinal tract 4. Corticobulbar tract Ventromedial System 1. Anterior corticospinal tract 2. Medial reticulospinal tract 3. Medial vestibulospinal tract 4. Lateral vestibulospinal tract 5. Tectospinal tract
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Descending tracts from cortex:  Lateral corticospinal tract (Dorsolateral System) Huge tract: ~ 1 million axons Function Voluntary control of distal muscles needed for
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/02/2010 for the course OT 441 taught by Professor Stein during the Summer '10 term at USC.

Page1 / 38

Lecture 11 - Descending Tracts - lecture - Higher Centers...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online